The present disclosure is directed to a method and apparatus for detecting a concentration of chemicals in a process stream in a refinery and, in particular, to using Surface Enhanced Raman Spectroscopy (SERS) to detect concentrations of molecular precursors to corrosive chemicals in hydrocarbon fluids.
Hydrocarbon fluids that are produced from a reservoir include a rich mixture of chemicals, some of which are provided naturally from the formation and some of which end up in the fluid during various stages of petroleum exploration, completion and/or production. Refineries receive feedstocks that include the hydrocarbon fluids and extract or separate out unwanted chemicals. Refinery feedstocks and process streams used in refineries often contain contaminant amines (e.g., from shale oils or upstream H2S scavenger treatments) which contribute to amine-HCl salt formation in distillation towers and overhead systems of the refinery. Amine-HCl salt corrosion is the most common form of corrosion impacting refinery crude processing units, and monoethanolamine (MEA) is one or the most common and problematic of the contaminant amines. In order to predict corrosion risk or mitigate corrosion cause by a chemical contaminant such as MEA from process streams, it is necessary to detect and determine the concentrations of the chemical in the process stream. Current methods of chemical concentration detection can take from days to weeks to obtain results. A rapid monitoring field method for easily measuring amine levels in process streams is therefore needed to allow an operator to take prompt and appropriate action to mitigate corrosion risk in refinery parts.